This application claims priority to Japanese Patent Application No. 2011-191460 filed on Sep. 2, 2011. The entire disclosure of Japanese Patent Application No. 2011-191460 is hereby incorporated herein by reference.
1. Technical Field
The present invention relates to a printing apparatus including a drying unit that blows out dry air to perform a drying process on a printing medium to which a liquid is adhered by a printing head, a curl correcting unit that corrects curling of the printing medium further to the downstream side of a transport direction of the printing medium than the drying unit.
2. Related Art
Generally, as a printing apparatus that adheres a liquid onto a printing medium to perform printing, an ink jet printing apparatus is widely known. In such a kind of printing apparatus, a drying device for drying the ink (liquid)-adhered printing medium in the course of transport is provided on the transport path of the printing medium (for example, JP-A-2009-045861 and JP-A-2009-179417).
For example, the drying device disclosed in JP-A-2009-045861 includes a suction intake fan for introducing air from the outside into a case, a heater for heating the air introduced into the case, an outlet for blowing the dry air formed by heating the air to the printing medium after the image printing, and a circulation space that leads the dry air blown from the outlet to the suction intake fan again. The dry air is circulated while being blown to the printing medium, the temperature of the dry air is increased (warmed up) to a target temperature (a predetermined temperature) for a short time, and the ink adhering to the printing medium is efficiently dried. The printing medium after the drying is discharged to the downstream side in the transport direction of the drying device.
In the printing device disclosed in JP-A-2009-179417, a de-curl mechanism that corrects curling the dry printing medium (sheet) after the printing is provided at a position further to the downstream side in the transport direction than the drying device. The de-curl mechanism is provided with a de-curl roller and a transport roller. When the curl correction is not performed, the de-curl roller is disposed at a non-de-curl position separated from the transport roller. When the curl correction is performed, the de-curl roller is disposed at a de-curl position coming into contact with the transport roller.
Under the drying device, the dried air (warm air) ejected from the outlet onto the surface of the printing medium remains between a pair of discharge rollers provided on the upstream side and the downstream side in the transport direction with respect to the outlet, and thus a relatively high temperature drying area is formed. When the printing medium after printing passes through the drying area, the drying of the ink is promoted by the heat of the heated air remaining in the drying area. However, there is a gap in a drying area forming member such as a discharge roller for forming the drying area, the warm air escapes from the gap, the temperature of the drying area decreases, and thus the drying efficiency is decreased.
In the printing apparatus provided with the de-curl mechanism disclosed in JP-A-2009-179417, the sheet is not transported during warming-up of the drying device, and thus the de-curl roller is disposed at the non-de-curl position. For this reason, the warm air exiting from the gap of the drying area forming member such as the discharge roller is discharged to the outside of the printing apparatus through a gap between the de-curl roller and the transport roller as a flow path, from the drying area formed under the drying device. When an air current in which the air of the drying area is discharged to the outside of the printing apparatus is generated, a necessary time until the temperature of the drying area reaches a temperature suitable for drying after the temperature increase of the drying device is started tends to be relatively increased, and a waiting time until it is possible to start printing after supplying power tends to be increased.